The present invention concerns an automatic analysis apparatus used for determining times for modifying the physical state of a fluid medium.
It applies particularly, but not exclusively, for determining timing blood coagulation in accordance with a method wherein the blood sample is arranged at the bottom of a cup containing a ferromagnetic ball driven in a periodic motion under the effect of an external magnetic field. The modifications of the movements of the ferromagnetic ball (for example the amplitude and/or frequency variations) representative of changes of the physical state of the blood are then detected with the aid of suitable means (opto-electronicsxe2x80x94inductive, capacitive, densitometric).
The principle of this detection is given in detail in the European patent No EP 88403279.8 filed in the name of the company SERBIO S.A.
IN an analysis apparatus of this type with a high rate (about 360 tests/hour), each cup for single usage has the shape of a small parallelepiped whose incurved bottom constitutes the rolling path of the ball, whereas the face opposite the bottom has an opening. These cups are arranged side by side and fixed so as to be detached from a flexible support strip which temporarily blocks off their openings. The strip equipped with cups can be wound onto a coil able to be engaged on a device provided in a storage and distribution compartment of a robot.
In this type of automatic machines whose failure rate, in all cases, is about 3 interventions/year, the cups are extracted from the strip so as to be then arranged in suitable locations inside the robot. Thus, these machines and sources of failures include relatively complex and expensive transfer and grasping means. They are suitable for laboratories having a large number of tests to be carried out in keeping with the previously mentioned rates and possessing a culture and special skills in the laboratory robots.
At the same time, there are available for use in small laboratories not having special skills in robots manual or semi-automatic machines having good reliability (intervention rate subsequent to failures, in all cases, of about 1 intervention/10 years).
Between the two types of devices previously mentioned, there is a gap to be filled corresponding to small ands average-sized automatic machines able to function at rates of between 60 and 120 tests/hour and of necessity possessing good reliability on account of the structure and skill of the laboratories for which these machines are intended.
The patent EP 0 525 273 A1 also concerns a device for determining blood coagulation time and introducing a plate on which a plurality of cavities are arranged in which balls are placed with the samples. This plate is subjected to a circular movement under the effect of a motor.
According to this document, an electronic camera takes a picture of the plate with all its cavities so as to detect ball movement variations.
However, the complexity of the solutions used for automation and its corresponding costs constitutes a drawback in small and medium-sized laboratories. First of all, this complexity is mainly due to handlings of the cups required in the analysis cycle for picking up said cups, detach them from the film, bring them into the measuring chamber and for extracting them following measurement with a view to discharging them into a discharge compartment, it being understood that these handlings have to be carried out owing to the nature of the means used for determining the blood coagulation time.
Thus, the aim of the invention is to embody an apparatus less expensive and having a simpler design than known devices, but which permits sufficient rates so as to be able to form part of the field of small and medium-sized devices. To this effect, the invention concerns an automatic analysis apparatus of the type in which a liquid sample to be analysed is arranged in a cup containing a ferromagnetic ball driven in a periodic movement under the effect of a magnetic field, this apparatus including an electronic camera orientated towards the cup, and a processor for detecting from the image of the cup the modifications of the movements of the ball.
According to the invention, this apparatus is characterised in that it uses a plurality of cups secured to a support strip moving past one by one in a detection station, and in that the detection station includes at last one electronic camera situated below the cups, and electromagnetic means placed laterally with respect to the strip at the right of the side faces of the cups so as to generate a magnetic field inside the movement axis of the ball contained in the cup located in the detection station, the running off movement of the strip able to be of the step-by-step or even continuous type.
Advantageously, the electronic camera shall be placed below the cup, the electromagnetic means for generating the external magnetic field then being arranged laterally inside the movement axis of the ball.
This association of camera and electromagnetic means is particularly suitable for the line detection of the movements of the balls contained in the cups.
In this case, the cups which remain fixed on the flexible support strip, are driven according to a step-by-step movement, indeed possibly continuous, along a path passing successively through a pipette station in which a reactive product is injected, a detection station including electromagnetic means placed laterally on either side of the strip, and at least one electronic camera placed under the path of the cups in the emission zone of the magnetic field, and a station for storing the used cups.
The pipette station could advantageously include a mobile pipette, both vertically and along a horizontal circular path so as to be able to occupy an injection position situated at the right of the path of the cups so as to allow reagents to be injected inside the latter, a rinsing position situated at the right of a rinsing cup and at least one reactive agent sampling position situated at the right of a sampling area of a reactive agent distributor.
This reactive agent distributor could consist of a carrousel including a plurality of cups of mobile reactive agents along a circular path so as to be able to be brought successively into the sampling area.
There now follows a description of one embodiment of the invention given by way of non-restrictive examples with reference to the accompanying drawings on which: